Dual hook hoist apparatus

ABSTRACT

A dual hook lifting assembly for a straddle type mobile lift and including a trolley which traverses the gantry crossbeam and carries a pair of sheaves for each hook mounted on the trolley&#39;&#39;s opposite sides. A wire rope having one end fixed and the other end connected to a winch drum, passes around a sheave on the hook block and up over each sheave on the trolley. A second reeve of wire is employed in a similar manner for the second hook.

United States Patent 1191 Scannell 1451 Apr. 23, 1974 DUAL HOOK HOIST APPARATUS [75] Inventor: Stephen J. Scannell, Milwaukee,

Wis.

[73] Assignee: Renner Manufacturing Company,

Milwaukee, Wis.

[22] Filed: Sept. 5, 1972 [21] Appl. No.: 286,565

52 U.S. c1 212/14, 212/11, 212/125 51 1111.01. B66c 17/04 58 Field of Search ..212/11,13, 14, 125;

214/392, 394; 254/144, 189; 294/67 R, 67 D, 67 DA, 81 R, 81 S, 81 F [56] References Cited UNITED STATES PATENTS 3,111,228 11/1963 Anderson; 212/11 X 2,656,196 10/1953 Fellabaum 212/11 X 9/1964 Bjorklund ..214/394 4/1966 Dechantsreiter ..212/11 Primary ExaminerRichard E. Aegerter Assistant Examiner-Johnny D. Cherry Attorney, Agent, or Firm-Fred Wiviott; Ralph C.

Hohenfeldt [57] ABSTRACT A dual hook lifting assembly for a straddle type mobile lift and including a trolley which traverses the gantry crossbeam and carries a pair of sheaves for each hook mounted on the trolleys opposite sides. A wire rope having one end fixed and the other end connected to a winch drum, passes around a sheave on the hook block and up over each sheave on the trolley. A second reeve of wire is employed in a similar manner for the second hook.

13 Claims, 6 Drawing Figures PATENTEI] APR 2 3 I974 SHEET 1 UF 3 DUAL HOOK HOIST APPARATUS BACKGROUND OF THE INVENTION This invention relates to a lifting device for simultaneously operating a pair of hooks and which has particular, but not exclusive application to mobile type lifts.

Mobile type lifts are commonly employed for lifting and moving large bulky objects, such as shipping containers, structural members, modular building sections and the like. Such devices are well known and generally include a pair of inverted U-shaped gantries comprising crossbeams spanning vertical legs which are supported at their lower ends on wheels. The two gantry assemblies are connected together by spaced side members and may include hoists mounted on the crossbeams of each gantry.

In addition to providing vertical lifting motion, it is desirable that such lift mechanisms be capable of traversing the load laterally without moving the straddle lift vehicle itself. Toward this end one prior art apparatus included a second horizontal beam movably supported beneath the gantry crossbeam and having a laterally movable hook carrying trolley. This limited the usable lift distance attainable on a given gantry because of the space requirement for the movable beam.

Another apparatus for providing traversability plus lifting capacity in prior art gantries includes a movable sheave carrying trolley mounted directly on the gantry crossbeam. To minimize twisting loads about the longitudinal axis of the gantry crossbeam, a reeve of wire rope is normally suspended from each of its opposite sides for sharing the load on the hook which they support. This minimizes the bending moment about the longitudinal axis of the crossbeam but necessitates a minimum of two reeves of wire rope for each hook.

Conventional straddle type mobile lifts are constructed for withstanding large vertical forces resulting from lifting heavy loads, but they have a substantially reduced capability of withstanding horizontal forces, especially those perpendicular to the spaced side members. For this reason when lifting large bulky objects, it is important to hold the load as stable as possible and to prevent the suspended load from swinging which would result in generation of horizontal force components on the lift structure. For added stability, such lifts may have two hooks on each gantry. The hooks may be spaced apart on each gantry and provide a four point connection with the load thus reducing swinging mo tion of the load. The use of two hooks on each gantry necessarily results in a complex lifting system involving multiple reeves of cable for each hook. Such a system is generally expensive because of the large number of parts and is also inefficient due to the multiplicity of sheaves required.

SUMMARY OF THE INVENTION It is an object of the invention to provide a new and improved dual hook lifting apparatus.

It is another object of the present invention to provide a dual hook hoisting apparatus for a straddle type mobile lifting device.

Another object of the invention is to provide a dual hook lifting apparatus having means for the selective adjustment of the horizontal spacing between the hooks.

In general terms, the invention comprises a dual hook hoist apparatus having two pairs of laterally spaced sheaves and a pair of wire ropes one of which extends around a sheave on each hook and both sheaves of a different one of the pairs of sheaves. The ends of each rope are coupled to a common drum assembly for simultaneously raising or lowering the two books. The sheaves may be mounted on a trolley to permit traversing of the load along the crossbeam of the straddle lift while maintaining the vertical position of the hooks constant.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a straddle type lifting device to which the invention is primarily directed;

FIG. 2 is a side elevational view of the lift mechanism according to a preferred embodiment of the present invention;

FIG. 3 is a top plan view of the trolley portion of the lift mechanism illustrated in FIG. 2;

FIG. 4 is a view taken along lines 44 of FIG. 2;

FIG. 5 is an enlarged view of the trolley taken along line 5-5 of FIG. 2; and

FIG. 6 is a schematic diagram of the hoist system according to the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1, the straddle type mobile crane to which the invention is particularly adaptable is shown to include a pair of U-shaped gantries which are connected by spaced side members 11. Each gantry includes a pair of vertical leg members 12 having support wheels 13 at their lower ends and connected by horizontal cross members 14 at their upper ends. Each gantry also carries a lifting assembly 15 which are identical and accordingly only one will be described for the sake of brevity. The lifting assemblies each includes a winch drum 16, a trolley 17, a pair of idler sheaves 18A and 18B and a pair of hook blocks 19A and 198.

The winch drum l6 and drive motor 16' are mounted on one of the vertical gantry legs 12. The hook blocks 19A and 19B are respectively positioned by wire ropes 20A and 20B and wound around the winch drum 16. The ropes 20 may be wound on the drum 16 in a suitable manner such that they are simultaneously wound or unwound.

As seen in FIGS. 2 and 3, the trolley 17 is mounted for movement on each of the gantry cross members 14 by means of wheels 24 which ride on flanges 25 extending laterally from each side of members 14. The trolleys 17 each include a frame assembly 26 having a transverse member 27 at each end for supporting a pair of brackets 28 which extend generally parallel to frame assembly 26. A shaft 29 passes through each bracket 28 and has the trolley wheels 24 and sheaves 30A, 31A, 30B and 318 respectively rotatably mounted thereon. The trolley wheels 24 are mounted on bearings 34 and rotate independently of their respective sheaves which are individually mounted on their own bearings 34'. The frame assembly 26 includes telescoping tubes 32 and 33 which carry the cross members 27 at their opposite ends. Tube 32 is hollow for receiving the smaller diameter tube 33.

The length of the trolley 17 may be adjusted by means of a releasable coupling assembly 35 having a pin 37 which is selectively insertable into a hole 38 formed in tube 32 and any one of a plurality of apertures 40 formed in tube 33. As seen more particularly in FIG. 5, the coupling assembly 35 includes a generally U-shaped bracket 41 attached to tube 32 adjacent hole 38 by suitable means, such as screws 42. The pin 37 has a ring 44 at its lower end, and a flange 45 between the tube 32 and the interior surface of bracket 41. A spring 46 surrounds pin 37 and biases the same upwardly through holes 38 and 40. If it is desired to change the length of trolley 17, ring 44 may be pulled down thereby disengaging the pin from the tubes so that the span between the wheel brackets may be modified. This allows the span to be adjusted for various width loads to keep the cables as vertical as possible and thereby decrease cable tension and structural stresses in the trolley.

The cross members 14 may be generally I-shaped in vertical cross section and have a central web 48 and flanges 25. As seen in FIGS. 2 and 4, the trolley 17 straddles the center web 48 of cross member 14 and wheels 24 ride on flanges 25. A reversible drive motor 49 coupled with suitable reduction gearing 50 drives a first sprocket 52 disposed on one end of beam 14. A second sprocket 53 is disposed at the opposite end of the beam and is coupled to sprocket 52 by a continuous chain drive 54. One link at each end of the chain 54 is affixed to the trolley bracket 22. In this manner, operation of motor 49 moves the trolley along member 14. The motor 49 may be of any type well known in the art and may be either electrically or hydraulically driven, for example.

The hook blocks 19A and 19B are shown in FIG. 2 to be identical and accordingly only hook block 19A will be described in detail. Hook block 19A consists of a sheave 60A rotatably mounted between parallel plates 63 and 64 which are held in a fixed parallel relationship by a bottom plate 65 and top cross member 66. A lift hook 67 is affixed to the bottom plate 65 and may be mounted for rotation about a vertical axis by means of a threaded hook shank 68 and nut 69.

The hoist drive system will now be explained by first referring to FIG. 6 which schematically illustrates the lifting assembly 15. As indicated above, the winch drum 16 has two strands of wire rope A and 20B, wound around -it and extending up and reeved over idler sheaves 18A and 188 which are journaled on the end of cross member 14. Tracing wire rope 20A, it is seen to be reeved over sheave A which is located on one side of the trolley 17, pass downwardly through sheave 60A carried by a hook block 19A, continue upwardly and over sheave 31A located on the opposite side of the trolley 17 and at the same end of the trolley as sheave 30. As seen in FIG. 4, the ends 72A and 72B of the rope are respectively dead ended to the cross member 14 by brackets 73A and 73B. It will be appreciated that since sheaves 18A 30A and 31A rotate about fixed axes and since one end of rope 20A is fixed at point 72A, the rotation of drum 16 will increase or decrease the unwound length of rope 20A thereby causing a raising or lowering of the hook block assembly 19A. Rope 20B follows a path similar to that of rope 20A and is reeved through sheaves 30B and 31B at the opposite end of the trolley from sheaves 30A and 31A. Thus, the rotation of the winch drum 16 will result in a simultaneous vertical movement of the two hook blocks 19A and 193. Since sheaves 30A and 31A and 30B and 31B rotate about shafts which are fixed to the trolley assembly, it will also be appreciated that as the trolley istraversed along the beam, for example in the direction of the arrow, both sheaves 30A and 30B will translate in the same direction and at the same rate so taht the hook 19A will remain at the same relative elevation. In this manner, the load can be traversed without vertical movement of the load.

It will be apparent from the description that each hook block 19A and 19B has a strand of wire rope extending upward to the trolley assembly with one strand reeved through a sheave 30A or 308 on one side of the trolley and the other strand reeved through a sheave 31A or 31B on the other side. Thus, when a load is imposed upon either lift hook 19A or 198, it will impose substantially equal downward forces on either-side of the trolley producing a minimum of torsional force upon the beam cross member 14.

The description of the present invention described herein above is intended to be illustrative only. Those skilled in the art will appreciate that the invention need not be limited to straddle type mobile lifts, but could be easily adapted for lifting apparatus located in stationary installations. Accordingly, the scope of the invention is to be gathered only from an interpretation of .the appended claims.

I claim:

1. Lifting apparatus including:

support means,

carrier means mounted for translational movement in a substantially horizontal path on said support means,

first and second pairs of sheave means, rotatably mounted in spaced relation on said carrier means, said first and second pairs of sheave means being space along said path, V

drum means rotatably mounted on said support means,

first and second spaced apart, independently supported lifting means each having a sheave means rotatably mounted thereon, said first and second lifting means being spaced along said path and each being substantially below said first and second pair of sheave means, respectively, and

first and second rope means each having one end fixed to said support means and its other end coupled to said drum means, one of said rope means also extending over each of the sheave means of said first pair and around the sheave means of said first lifting means and said second rope means extending over each of the sheave means of said second pair and aroundthe sheave means of said second lifting means.

2. The apparatus set forth in claim 1 wherein the sheave means of said first pair are rotatably mounted "about a common, substantially horizontal first axis and the sheave means of said second pair are rotatably mounted about a common substantially hori; zontal second axis spaced from said first axis, each of said sheave means of said first and second pairs being mounted on opposite sides of said carrier means.

3. The apparatus set forth in claim 1 wherein said path extends between the fixed end of each of said first and second rope means and said drum means, said drum means being rotatable about an axis lying in a plane substantially normal to said path.

4. The apparatus set forth in claim 1 wherein said a r mean .i elss a .,,.P9EfiQl qt, vmaet ina.

said first pair of sheave means and a second portion for supporting said second pair of sheave means and adjustable coupling means for coupling said first and sec-- ond portions for selectively varying the distance between said first and second pair of sheave means.

5. The apparatus set forth in claim 1 and including a third pair of sheaves rotatably mounted on said support means between said carrier means and said drum means, each of said first and second rope means extending over one of the sheaves of said third pair.

6. The apparatus set forth in claim 5 wherein said path extends between the fixed end of each of said first and second rope means and said drum means, said drum means being rotatable about an axis lying in a plane substantially normal to said path.

7. The apparatus set forth in claim 6 wherein said carrier means includes a first portion for supporting said first pair of sheave means and a second portion for supporting said second pair of sheave means and adjustable coupling means for coupling said first and second portions for selectively varying the distance between said first and second pair of sheave means.

8. The apparatus set forth in claim 1 wherein said support means comprises a straddle type mobile crane including a pair of spaced gantries having side memcross member and side members and between said carrier means and said drum means, each of said first and second rope means extending over one of the sheaves of said third pair.

10. The apparatus set forth in claim 9 wherein the sheaves of each of said first and second pairs of sh eaye means are mounted for rotation about substantially horizontal axes, each of the sheave means of said first and second pairs being independently rotatably mounted on opposite sides of said carrier means.

11. The apparatus set forth in claim 10 wherein said path extends between the fixed end of each of said first and second rope means and said drum means, said drum means being rotatable about an axis lying in a plane substantially normal to said path.

12. The apparatus set forth in claim 11 wherein said carrier means includes a first portion for supporting said first pair of sheave means and a second portion for supporting said second pair of sheave means and adjustable coupling means for coupling said first and second portions for selectively varying the distance between said first and second pair of sheave means.

13. The apparatus set forth in claim 12 and including a second carrier means mounted on the second cross member of said second gantry, said second carrier means including two pairs of sheave means, drum means, and first and second lifting means all arranged identically to those associated with said first carrier means and cross member. 

1. Lifting apparatus including: support means, carrier means mounted for translational movement in a substantially horizontal path on said support means, first and second pairs of sheave means rotatably mounted in spaced relation on said carrier means, said first and second pairs being spaced along said path, drum means rotatably mounted on said support means, first and second spaced apart, independently supported lifting means each having a sheave means rotatably mounted thereon, said first and second lifting means being spaced along said path and each being substantially below said first and second pair of sheave means, respectively, and first and second rope means each having one end fixed to said support means and its other end coupled to said drum means one of said rope means also extending over each of the sheaves of said first pair and around the sheave of said first lifting means and said second rope means extending over each of the sheaves of said second pair and around the sheave of said second lifting means.
 2. The apparatus set forth in claim 1 wherein the sheaves of said first pair are rotatably mounted about a common, substantially horizontal first axis and the sheaves of said second pair are rotatably mounted about a common substantially horizontal second axis spaced from said first axis, each of said sheaves of said first and second pairs being mounted on opposite sides of said carrier means.
 3. The apparatus set forth in claim 1 wherein said path extends between the fixed end of each of said first and second rope means and said drum means, said drum means being rotatable about an axis lying in a plane substantially normal to said path.
 4. The apparatus set forth in claim 1 wherein said carrier means includes a first portion for supporting said first pair of sheave means and a second portion for supporting said second pair of sheave means and adjustable coupling means for coupling said first and second portions for selectively varying the distance between said first and second pair of sheave means.
 5. The apparatus set forth in claim 1 and including a third pair of sheaves rotatably mounted on said support means between said carrier means and said drum means, each of said first and second rope means extending over one of the sheaves of said third pair.
 6. The apparatus set forth in claim 5 wherein said path extends between the fixed end of each of said first and second rope means and said drum means, said drum means being rotatable about an axis lying in a plane substantially normal to said path.
 7. The apparatus set forth in claim 6 wherein said carrier means includes a first portion for supporting said first pair of sheave means and a second portion for supporting said second pair of sheave means and adjustable coupling means for coupling said first and second portions for selectively varying the distance between said first and second pair of sheave means.
 8. The apparatus set forth in claim 1 wherein said support means comprises a straddle type mobile crane including a pair of spaced gantries having side members, at least one cross member extending between said gantry side members and being affixed thereto, said carrier means being mounted on one of said cross members.
 9. The apparatus set forth in claim 8 and including a third pair of sheaves rotatably mounted on one of said cross member and side members and between said carrier means and said drum means, each of said first and second rope means extending over one of the sheaves of said third pair.
 10. The apparatus set forth in claim 9 wherein the sheaves of each of said first and second pairs of sheaves are mounted for rotation aBout substantially horizontal axes, each of the sheaves of said first and second pairs being independently rotatably mounted on opposite sides of said carrier means.
 11. The apparatus set forth in claim 10 wherein said path extends between the fixed end of each of said first and second rope means and said drum means, said drum means being rotatable about an axis lying in a plane substantially normal to said path.
 12. The apparatus set forth in claim 11 wherein said carrier means includes a first portion for supporting said first pair of sheave means and a second portion for supporting said second pair of sheave means and adjustable coupling means for coupling said first and second portions for selectively varying the distance between said first and second pair of sheave means.
 13. The apparatus set forth in claim 12 and including a second carrier means mounted on the second cross member of said second gantry, said second carrier means including two pairs of sheave means, drum means, and first and second lifting means all arranged identically to those associated with said first carrier means and cross member. 